Buñag R D, Inoue A
Proc Soc Exp Biol Med. 1985 Jan;178(1):91-100. doi: 10.3181/00379727-178-41988.
Sensitivity of the ventromedial hypothalamus (VMH) to electrical stimulation was compared with that of the locus coeruleus (LC) in urethane-anesthetized rats. Based not only on current strengths required to elicit threshold effects, but also on magnitude of pressor responses to suprathreshold stimulation, the LC was consistently more sensitive than the VMH. Despite this greater pressor sensitivity, splanchnic nerve firing increased almost equally upon stimulation of either brain area. Similar comparisons made in other rats following bilateral adrenalectomy or pretreatment with a vasopressin antagonist showed no significant alteration of pressor and sympathetic responsiveness to stimulation of either the LC or the VMH. When frequency of neural firing was recorded from a lumbar sympathetic trunk instead of the splanchnic nerve, increases in sympathetic nerve activity produced by LC stimulation were significantly larger than those produced from the VMH. The results suggest that greater pressor sensitivity of the LC is due, at least in part, to stronger constriction in vascular beds innervated by the lumbar sympathetic chains.
在乌拉坦麻醉的大鼠中，比较了腹内侧下丘脑（VMH）和蓝斑（LC）对电刺激的敏感性。不仅基于引发阈值效应所需的电流强度，还基于对阈上刺激的升压反应幅度，LC始终比VMH更敏感。尽管LC具有更高的升压敏感性，但在刺激任一脑区时，内脏神经放电几乎同等程度地增加。在双侧肾上腺切除或用血管加压素拮抗剂预处理后的其他大鼠中进行的类似比较表明，对LC或VMH刺激的升压和交感反应性没有显著改变。当从腰交感干而非内脏神经记录神经放电频率时，LC刺激产生的交感神经活动增加明显大于VMH刺激产生的增加。结果表明，LC更高的升压敏感性至少部分归因于腰交感链支配的血管床更强的收缩。
